How Gutenberg uses AJAX for WP REST API requests

Last Updated on December 25, 2020 by Neil Murray

Gutenberg uses external thin jQuery.ajax wrapper for WP REST API requests as documented here:

https://herregroen.github.io/wordpress-jsdoc/api-request.js.html

It is enqueue from https://github.com/WordPress/gutenberg/blob/master/lib/client-assets.php#L294

gutenberg_register_vendor_script(
    'wp-api-request-shim',
    'https://rawgit.com/WordPress/wordpress-develop/master/src/wp-includes/js/api-request.js'
);

and built in /vendor/ directory.

Latest version of WordPress includes the file in /wp-includes/js/

https://github.com/WordPress/WordPress/blob/master/wp-includes/js/api-request.js